Cognitive Conditioned Pain Modulation

NCT ID: NCT07234123

Last Updated: 2026-01-07

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 24 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-08-09
• Study Completion Date: 2025-05-29

Brief Summary

This "pain reduces pain" study looks at how the brain reduces pain when a person feels two painful sensations at the same time. There is considerable evidence that the brain can "turn down" pain using natural endogenous pain-control systems. The current CPM study measures whether attentional processes can also make a measurable contribution to pain inhibition alongside neurochemical mechanisms.

Detailed Description

Conditioned pain modulation (CPM) is a natural process where feeling pain in one part of the body (e.g., a conditioning stimulus to the wrist) can reduce pain felt in another part of the body (a test stimulus to the foot). There is considerable evidence from both animal and human studies that the painful conditioning stimulus can stimulate the brain to activate neurochemical pain-control pathways (e.g., endogenous opioids), which are believed to take 30-120 seconds to fully engage. The current CPM study measures whether attentional processes can also make a measurable contribution to pain inhibition alongside neurochemical mechanisms.

Primary measures: Graphic ratings scale "worst pain" ratings.

The primary measure of the current study graphic ratings scales (worst pain ratings) will measure how much pain participants feel on their foot during foot only (test stimulus), vs. how much pain participants feel on their foot (test stimulus during simultaneous foot (test stimulus) + wrist (conditioning stimulus).

The current investigators predict that pain (e.g., the conditioning stimulus) naturally demands attention and can pull attention away from the original pain source (the test stimulus), resulting in CPM-like reductions in pain of the test stimulus.

Secondary measure #1. Cognitive measures are introduced in the current study, to quantify how much (if at all) the conditioning stimulus reduces pain of the target stimulus via attentional mechanisms. Participants estimate what percentage of their attention was directed to their foot (the test stimulus) during foot only vs. during foot + wrist (test + conditioning stimulus). This will measure whether the conditiioning stimulus to the wrist reduces how much attention participants focus on their foot. Analyses will also measure whether the amount of attention shift away from the foot (via participants; subjective ratings) is correlated with CPM robustness (reduction in pain of foot during duel stimulation).

Secondary measure #2. As another secondary measure of attention during one vs. two simultaneous pain stimuli, this study involves a divided attention auditory listening task that becomes harder when pain demands more attention (Craik et al., odd number divided attention task during single test pain stimuli vs. simultaneous test + conditioning stimuli). The more errors the participant makes on the divided attention task, the more attention diverted away from the auditory task by pain. Analyses will measure whether the number of errors on the divided attention task is correlated with CPM robustness (reduction in pain of foot, during duel thermal stimulation).

Exploratory measures. As exploratory measures, participants will rate how distracted they were and how difficult it was to concentrate (on 0-10 rating scales during test stimulus alone verses test + conditioning noxious thermal heat stimuli).

In summary, embedding these cognitive measures into the CPM protocol may enhance mechanistic interpretation accuracy by quantifying attentional contributions to pain inhibition in specific CPM protocols, thereby complementing existing approaches to pain phenotyping and reducing unexplained variance in CPM outcomes.

Conditions

Healthy Participants

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

Single pain stimulus

test pain stimulus alone

Group Type: EXPERIMENTAL

test stimulus

Intervention Type: BEHAVIORAL

single brief stimulus to foot only

dual pain stimuli

simultaneous foot (test stimulus + wrist (conditioning stimulus)

Group Type: EXPERIMENTAL

conditioned pain modulation

Intervention Type: BEHAVIORAL

simultaneous stimuli to foot (test stimulus) and wrist (conditioning stimulus)

Interventions

conditioned pain modulation

simultaneous stimuli to foot (test stimulus) and wrist (conditioning stimulus)

Intervention Type: BEHAVIORAL

test stimulus

single brief stimulus to foot only

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• Only University of Washington students in eligible psychological courses are
• eligible. General public is not eligible.
• Enrolled psychology students fluent in English,
• Age ≥18 y, able to follow instructions.

Exclusion Criteria

• Seizure history,
• Migraines,
• Diabetes,
• Extreme pain insensitivity,
• Motion sickness,
• or prior participation in this protocol.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Mayday Fund

OTHER

Sponsor Role: collaborator

University of Washington

OTHER

Sponsor Role: lead

Responsible Party

Hunter Hoffman

Research Scientist

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Hunter Hoffman

Role: PRINCIPAL_INVESTIGATOR

University of Washington

Locations

University of Washington Seattle

Seattle, Washington, United States

Countries

United States

References

Yarnitsky D. Conditioned pain modulation (the diffuse noxious inhibitory control-like effect): its relevance for acute and chronic pain states. Curr Opin Anaesthesiol. 2010 Oct;23(5):611-5. doi: 10.1097/ACO.0b013e32833c348b.

Reference Type: BACKGROUND

PMID: 20543676 (View on PubMed)

Other Identifiers

CPM2025

Identifier Type: -

Identifier Source: org_study_id